"open seasame" was one id didn't get for the longest time, i thought it was referring to sesame seeds on a bagel or burger buns.
Well i was with my dad one day, when i was about 10 or 11 and i said it to open an automatic slider door at the grocery store. I started to say it slowly, until I realized it's just "open says me" really fast. that realization made me feel smart for the next few days.